The present invention relates to automatically aligning a robotic arm, particularly in three dimensions. In particular, the present invention relates to aligning a metering arm in automated diagnostic analyzers.
Known diagnostic analyzers include immunodiagnostic analyzers such as the Vitros® ECi immunodiagnostic analyzer, or clinical chemistry analyzers such as the Vitros® 5,1 FS, both sold by Ortho-Clinical Diagnostics, Inc. All such analyzers are collectively called automated diagnostic analyzers.
Representative systems are disclosed, for example, in U.S. Published Patent Application No. 2003/0026733 and in U.S. Provisional Application No. 60/832,045 filed Jul. 20, 2006, both of which are incorporated herein by reference in their entireties. Such systems have liquid handling systems, for aspirating/dispensing a liquid such as sample or reagent. Such systems typically include a metering probe for dispensing/aspirating a liquid located on the end of a movable metering arm.
For example, as disclosed in the '045 application, the metering system includes one and sometimes two robotic arms that have the capability to move not only linearly but also rotate in a plane that is horizontal and parallel to the line of linear motion in addition to being able to move in a vertical (z-direction) to enable sample acquisition or expulsion or as well as reagent acquisition or expulsion. The robotic arms and metering heads are required to be able to position to discrete points within a reachable space, but they are physically capable of positioning anywhere within that space. Nothing physically limits the arm from reaching only a discrete touch point. A typical metering system(s) include four major elements as follows:                (1) A linear track or guide rail where the position of a truck containing a specific robotic arm on the track is controlled by its own servo or stepper motor or means for moving the arm in a forward or backward linear fashion.        (2) Robotic arm(s) capable of movement via the truck along the linear track and capable of pivoting at any point on the linear track in a plane that is horizontal and parallel to the linear track.        (3) A means, such as a metering head for sample acquisition and expulsion or reagent acquisition and expulsion attached to the end of each robotic arm.        (4) A means for vertical (z-direction) movement of the sample or reagent handling means at the ends of the robotic arms.        
In one embodiment as shown in the figures, a diagnostic analyzer includes both a dry system A and a wet system B. A guide rail 2 is positioned along at least a part of the length of the analyzer. The embodiment of FIG. 1 shows both a metering system for the dry system and a metering system for the wet system. Common features of the metering system for the wet system are depicted using the same reference numeral as the dry system, except with the addition of a prime (′). The metering system includes truck 1 that moves along the guide rail 2. Pivotably attached through axis (C) (FIG. 3) to truck 1 is robotic arm 3. As FIG. 1 depicts, the robotic arm 1 is pivotable and moves through plane 4. Attached to robotic arm 1 is metering head 5. FIG. 3 shows metering head 5 in more detail. Metering head 5 includes a probe 6 also called a proboscis. The probe may include a disposable tip or may be non-disposable washable probe. As described above, the probe is movable in the vertical direction to access sample and/or reagent.
FIG. 4 shows the robotic arm 3 and metering head 5 accessing multiple (in this embodiment four) rotatable sample trays 20 having sample tubes 21 (in this embodiment ten sample tubes). As FIG. 4 depicts, the metering system is able to access the sample tubes in more than a single dimension (i.e., along the length of the guide rail). That is, the metering system by virtue of the pivotable robotic arm is able to move in an x, y, and z direction and thus able to access all areas of all of the sample trays 20.
The alignment of such metering arms on automated diagnostic analyzers needs to be verified and/or re-aligned at specified intervals to insure the performance of the metering system. Currently the alignment is performed manually by manufacturing or service personnel, which is time consuming and subject to human errors. It would be very desirable to automate this metering arm alignment procedure so that trained personnel are not needed and any operator could initiate the alignment process.
U.S. Pat. No. 6,937,955 discloses calibrating a metering arm on a clinical analyzer, which is incorporated herein by reference in its entirety.
For the foregoing reasons, there is a need for a method of automatically aligning a robotic arm to obviate the need to have manufacturing or service operator do the same.